Here is the full list of all 36 Valkyria Chronicles 4 achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Recruited all squad members.
One of your classes was promoted to Paragon status.
Kept your promise with Riley Miller.
Learned all orders.
Completed Chapter 18, and ended Belgar's dark ambitions.
Completed Chapter 17, and witnessed the end of the war.
Defeated 1000 enemy units.
Completed Chapter 15, and defeated both Walz and Crymaria.
Gave orders 15 times.
Developed the Hafen into a heavy tank.
Obtained A ranks on 20 missions.
Defeated 15 enemy aces.
Completed Chapter 11, and made it past the Sea Fortress.
Earned 1,000,000 DCT cumulatively.
Completed Chapter 7, and rendezvoused with the Centurion.
Completed 10 missions without anyone in critical condition.
Learned an order at the Mess Hall for the first time.
Completed a squad story for the first time.
One of your classes was promoted to Elite status.
Completed Chapter 4, and won the battle of Siegval.
One of your squadmates was promoted to Corporal.
Rescued 10 allies in critical condition.
Defeated an enemy ace for the first time.
Used R&D Facility for the first time.
Obtained an A rank on a mission for the first time.
Obtained all achievements.
Obtained all decorations.
Watched all event scenes.
Obtained all infantry weapons.
Obtained all tank parts.
Obtained all ship parts.
All of your classes were upgraded to max level.
Obtained A ranks on all missions.
Gave ship orders 15 times.
Gave direct commands 15 times.
Triggered a Last Stand 15 times.